From 99b1c31b2dfd1a59f7a280465f50995ada76d0d5 Mon Sep 17 00:00:00 2001
From: Sylvain Wallez <sylvain@elastic.co>
Date: Fri, 4 Nov 2022 09:31:45 +0100
Subject: [PATCH] Add Type in addition to Class to map types with generic
 parameters (#438)

---
 .../java/co/elastic/clients/ApiClient.java    |  7 ++--
 .../clients/json/DelegatingJsonpMapper.java   |  5 ++-
 .../co/elastic/clients/json/JsonData.java     | 13 +++++++
 .../co/elastic/clients/json/JsonDataImpl.java | 20 ++++++++--
 .../clients/json/JsonpDeserializer.java       | 15 ++++++--
 .../co/elastic/clients/json/JsonpMapper.java  | 10 ++++-
 .../elastic/clients/json/JsonpMapperBase.java | 37 +++++++++++-------
 .../clients/json/SimpleJsonpMapper.java       | 11 +++---
 .../json/jackson/JacksonJsonpMapper.java      | 13 ++++---
 .../clients/json/jsonb/JsonbJsonpMapper.java  | 13 ++++---
 .../MissingRequiredPropertyException.java     |  5 ++-
 .../elasticsearch/json/JsonpMapperTest.java   | 38 +++++++++++++++++++
 .../elasticsearch/model/ModelTestCase.java    | 11 +++++-
 13 files changed, 152 insertions(+), 46 deletions(-)

diff --git a/java-client/src/main/java/co/elastic/clients/ApiClient.java b/java-client/src/main/java/co/elastic/clients/ApiClient.java
index 29f03c3f9..0b46e12b9 100644
--- a/java-client/src/main/java/co/elastic/clients/ApiClient.java
+++ b/java-client/src/main/java/co/elastic/clients/ApiClient.java
@@ -26,6 +26,7 @@
 import co.elastic.clients.json.JsonpMapperBase;
 
 import javax.annotation.Nullable;
+import java.lang.reflect.Type;
 import java.util.function.Function;
 
 public abstract class ApiClient<T extends Transport, Self extends ApiClient<T, Self>> {
@@ -38,14 +39,14 @@ protected ApiClient(T transport, TransportOptions transportOptions) {
         this.transportOptions = transportOptions;
     }
 
-    protected <V> JsonpDeserializer<V> getDeserializer(Class<V> clazz) {
+    protected <V> JsonpDeserializer<V> getDeserializer(Type type) {
         // Try the built-in deserializers first to avoid repeated lookups in the Jsonp mapper for client-defined classes
-        JsonpDeserializer<V> result = JsonpMapperBase.findDeserializer(clazz);
+        JsonpDeserializer<V> result = JsonpMapperBase.findDeserializer(type);
         if (result != null) {
             return result;
         }
 
-        return JsonpDeserializer.of(clazz);
+        return JsonpDeserializer.of(type);
     }
 
     /**
diff --git a/java-client/src/main/java/co/elastic/clients/json/DelegatingJsonpMapper.java b/java-client/src/main/java/co/elastic/clients/json/DelegatingJsonpMapper.java
index c4b69a647..c43aabf72 100644
--- a/java-client/src/main/java/co/elastic/clients/json/DelegatingJsonpMapper.java
+++ b/java-client/src/main/java/co/elastic/clients/json/DelegatingJsonpMapper.java
@@ -24,6 +24,7 @@
 import jakarta.json.stream.JsonParser;
 
 import javax.annotation.Nullable;
+import java.lang.reflect.Type;
 
 public abstract class DelegatingJsonpMapper implements JsonpMapper {
 
@@ -39,8 +40,8 @@ public JsonProvider jsonProvider() {
     }
 
     @Override
-    public <T> T deserialize(JsonParser parser, Class<T> clazz) {
-        return mapper.deserialize(parser, clazz);
+    public <T> T deserialize(JsonParser parser, Type type) {
+        return mapper.deserialize(parser, type);
     }
 
     @Override
diff --git a/java-client/src/main/java/co/elastic/clients/json/JsonData.java b/java-client/src/main/java/co/elastic/clients/json/JsonData.java
index 9ff1950ff..1016b9ffd 100644
--- a/java-client/src/main/java/co/elastic/clients/json/JsonData.java
+++ b/java-client/src/main/java/co/elastic/clients/json/JsonData.java
@@ -26,6 +26,7 @@
 import java.io.InputStream;
 import java.io.Reader;
 import java.io.StringReader;
+import java.lang.reflect.Type;
 import java.util.EnumSet;
 
 /**
@@ -59,11 +60,23 @@ public interface JsonData extends JsonpSerializable {
      */
     <T> T to(Class<T> clazz);
 
+    /**
+     * Converts this object to a target type. A mapper must have been provided at creation time.
+     *
+     * @throws IllegalStateException if no mapper was provided at creation time.
+     */
+    <T> T to(Type type);
+
     /**
      * Converts this object to a target class.
      */
      <T> T to(Class<T> clazz, JsonpMapper mapper);
 
+    /**
+     * Converts this object to a target type.
+     */
+    <T> T to(Type type, JsonpMapper mapper);
+
     /**
      * Converts this object using a deserializer. A mapper must have been provided at creation time.
      *
diff --git a/java-client/src/main/java/co/elastic/clients/json/JsonDataImpl.java b/java-client/src/main/java/co/elastic/clients/json/JsonDataImpl.java
index 1150c4ddc..ee1745aed 100644
--- a/java-client/src/main/java/co/elastic/clients/json/JsonDataImpl.java
+++ b/java-client/src/main/java/co/elastic/clients/json/JsonDataImpl.java
@@ -25,6 +25,7 @@
 
 import java.io.StringReader;
 import java.io.StringWriter;
+import java.lang.reflect.Type;
 
 class JsonDataImpl implements JsonData {
     private final Object value;
@@ -65,19 +66,30 @@ public JsonValue toJson(JsonpMapper mapper) {
 
     @Override
     public <T> T to(Class<T> clazz) {
+        return to((Type)clazz, null);
+    }
+
+    @Override
+    public <T> T to(Type clazz) {
         return to(clazz, null);
     }
 
     @Override
     public <T> T to(Class<T> clazz, JsonpMapper mapper) {
-        if (clazz.isAssignableFrom(value.getClass())) {
-            return (T) value;
+        return to((Type)clazz, mapper);
+    }
+
+    @Override
+    public <T> T to(Type type, JsonpMapper mapper) {
+        if (type instanceof Class<?> && ((Class<?>)type).isAssignableFrom(value.getClass())) {
+            @SuppressWarnings("unchecked")
+            T result = (T) value;
+            return result;
         }
 
         mapper = getMapper(mapper);
-
         JsonParser parser = getParser(mapper);
-        return mapper.deserialize(parser, clazz);
+        return mapper.deserialize(parser, type);
     }
 
     @Override
diff --git a/java-client/src/main/java/co/elastic/clients/json/JsonpDeserializer.java b/java-client/src/main/java/co/elastic/clients/json/JsonpDeserializer.java
index 345dd4d44..ce57ded84 100644
--- a/java-client/src/main/java/co/elastic/clients/json/JsonpDeserializer.java
+++ b/java-client/src/main/java/co/elastic/clients/json/JsonpDeserializer.java
@@ -25,6 +25,7 @@
 import jakarta.json.stream.JsonParser.Event;
 
 import java.io.StringReader;
+import java.lang.reflect.Type;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Map;
@@ -88,15 +89,23 @@ default V deserialize(JsonParser parser, JsonpMapper mapper) {
 
     //---------------------------------------------------------------------------------------------
 
+//    /**
+//     * Creates a deserializer for a class that delegates to the mapper provided to
+//     * {@link #deserialize(JsonParser, JsonpMapper)}.
+//     */
+//    static <T>JsonpDeserializer<T> of(Class<T> clazz) {
+//        return of((Type)clazz);
+//    }
+
     /**
-     * Creates a deserializer for a class that delegates to the mapper provided to
+     * Creates a deserializer for a type that delegates to the mapper provided to
      * {@link #deserialize(JsonParser, JsonpMapper)}.
      */
-    static <T>JsonpDeserializer<T> of (Class<T> clazz) {
+    static <T>JsonpDeserializer<T> of(Type type) {
         return new JsonpDeserializerBase<T>(EnumSet.allOf(JsonParser.Event.class)) {
             @Override
             public T deserialize(JsonParser parser, JsonpMapper mapper) {
-                return mapper.deserialize(parser, clazz);
+                return mapper.deserialize(parser, type);
             }
 
             @Override
diff --git a/java-client/src/main/java/co/elastic/clients/json/JsonpMapper.java b/java-client/src/main/java/co/elastic/clients/json/JsonpMapper.java
index a4a259875..e3b02c4de 100644
--- a/java-client/src/main/java/co/elastic/clients/json/JsonpMapper.java
+++ b/java-client/src/main/java/co/elastic/clients/json/JsonpMapper.java
@@ -24,6 +24,7 @@
 import jakarta.json.stream.JsonParser;
 
 import javax.annotation.Nullable;
+import java.lang.reflect.Type;
 
 /**
  * A {@code JsonpMapper} combines a JSON-P provider and object serialization/deserialization based on JSON-P events.
@@ -44,7 +45,14 @@ public interface JsonpMapper {
     /**
      * Deserialize an object, given its class.
      */
-    <T> T deserialize(JsonParser parser, Class<T> clazz);
+    default <T> T deserialize(JsonParser parser, Class<T> clazz) {
+        return deserialize(parser, (Type)clazz);
+    }
+
+    /**
+     * Deserialize an object, given its type.
+     */
+    <T> T deserialize(JsonParser parser, Type type);
 
     /**
      * Serialize an object.
diff --git a/java-client/src/main/java/co/elastic/clients/json/JsonpMapperBase.java b/java-client/src/main/java/co/elastic/clients/json/JsonpMapperBase.java
index f24b3daf5..5f1f2594a 100644
--- a/java-client/src/main/java/co/elastic/clients/json/JsonpMapperBase.java
+++ b/java-client/src/main/java/co/elastic/clients/json/JsonpMapperBase.java
@@ -25,6 +25,7 @@
 
 import javax.annotation.Nullable;
 import java.lang.reflect.Field;
+import java.lang.reflect.Type;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
@@ -32,7 +33,7 @@
 public abstract class JsonpMapperBase implements JsonpMapper {
 
     /** Get a serializer when none of the builtin ones are applicable */
-    protected abstract <T> JsonpDeserializer<T> getDefaultDeserializer(Class<T> clazz);
+    protected abstract <T> JsonpDeserializer<T> getDefaultDeserializer(Type type);
 
     private Map<String, Object> attributes;
 
@@ -61,29 +62,39 @@ protected JsonpMapperBase addAttribute(String name, Object value) {
     }
 
     @Override
-    public <T> T deserialize(JsonParser parser, Class<T> clazz) {
-        JsonpDeserializer<T> deserializer = findDeserializer(clazz);
+    public <T> T deserialize(JsonParser parser, Type type) {
+        JsonpDeserializer<T> deserializer = findDeserializer(type);
         if (deserializer != null) {
             return deserializer.deserialize(parser, this);
         }
 
-        return getDefaultDeserializer(clazz).deserialize(parser, this);
+        @SuppressWarnings("unchecked")
+        T result = (T)getDefaultDeserializer(type).deserialize(parser, this);
+        return result;
     }
 
     @Nullable
-    @SuppressWarnings("unchecked")
     public static <T> JsonpDeserializer<T> findDeserializer(Class<T> clazz) {
-        JsonpDeserializable annotation = clazz.getAnnotation(JsonpDeserializable.class);
-        if (annotation != null) {
-            try {
-                Field field = clazz.getDeclaredField(annotation.field());
-                return (JsonpDeserializer<T>)field.get(null);
-            } catch (Exception e) {
-                throw new RuntimeException("No deserializer found in '" + clazz.getName() + "." + annotation.field() + "'");
+        return findDeserializer((Type)clazz);
+    }
+
+    @Nullable
+    @SuppressWarnings("unchecked")
+    public static <T> JsonpDeserializer<T> findDeserializer(Type type) {
+        if (type instanceof Class<?>) {
+            Class<?> clazz = (Class<?>)type;
+            JsonpDeserializable annotation = clazz.getAnnotation(JsonpDeserializable.class);
+            if (annotation != null) {
+                try {
+                    Field field = clazz.getDeclaredField(annotation.field());
+                    return (JsonpDeserializer<T>)field.get(null);
+                } catch (Exception e) {
+                    throw new RuntimeException("No deserializer found in '" + clazz.getName() + "." + annotation.field() + "'");
+                }
             }
         }
 
-        if (clazz == Void.class) {
+        if (type == Void.class) {
             return (JsonpDeserializer<T>)JsonpDeserializerBase.VOID;
         }
 
diff --git a/java-client/src/main/java/co/elastic/clients/json/SimpleJsonpMapper.java b/java-client/src/main/java/co/elastic/clients/json/SimpleJsonpMapper.java
index 98591b3d7..67a37428e 100644
--- a/java-client/src/main/java/co/elastic/clients/json/SimpleJsonpMapper.java
+++ b/java-client/src/main/java/co/elastic/clients/json/SimpleJsonpMapper.java
@@ -23,6 +23,7 @@
 import jakarta.json.spi.JsonProvider;
 import jakarta.json.stream.JsonGenerator;
 
+import java.lang.reflect.Type;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -37,8 +38,8 @@ public class SimpleJsonpMapper extends JsonpMapperBase {
     public static SimpleJsonpMapper INSTANCE = new SimpleJsonpMapper(true);
     public static SimpleJsonpMapper INSTANCE_REJECT_UNKNOWN_FIELDS = new SimpleJsonpMapper(false);
 
-    private static final Map<Class<?>, JsonpSerializer<?>> serializers = new HashMap<>();
-    private static final Map<Class<?>, JsonpDeserializer<?>> deserializers = new HashMap<>();
+    private static final Map<Type, JsonpSerializer<?>> serializers = new HashMap<>();
+    private static final Map<Type, JsonpDeserializer<?>> deserializers = new HashMap<>();
 
     static {
         serializers.put(String.class, (JsonpSerializer<String>) (value, generator, mapper) -> generator.write(value));
@@ -117,14 +118,14 @@ public <T> void serialize(T value, JsonGenerator generator) {
     }
 
     @Override
-    protected <T> JsonpDeserializer<T> getDefaultDeserializer(Class<T> clazz) {
+    protected <T> JsonpDeserializer<T> getDefaultDeserializer(Type type) {
         @SuppressWarnings("unchecked")
-        JsonpDeserializer<T> deserializer = (JsonpDeserializer<T>) deserializers.get(clazz);
+        JsonpDeserializer<T> deserializer = (JsonpDeserializer<T>) deserializers.get(type);
         if (deserializer != null) {
             return deserializer;
         } else {
             throw new JsonException(
-                "Cannot find a deserializer for type " + clazz.getName() +
+                "Cannot find a deserializer for type " + type.getTypeName() +
                     ". Consider using a full-featured JsonpMapper"
             );
         }
diff --git a/java-client/src/main/java/co/elastic/clients/json/jackson/JacksonJsonpMapper.java b/java-client/src/main/java/co/elastic/clients/json/jackson/JacksonJsonpMapper.java
index 54a009d74..ffa352240 100644
--- a/java-client/src/main/java/co/elastic/clients/json/jackson/JacksonJsonpMapper.java
+++ b/java-client/src/main/java/co/elastic/clients/json/jackson/JacksonJsonpMapper.java
@@ -32,6 +32,7 @@
 import jakarta.json.stream.JsonParser;
 
 import java.io.IOException;
+import java.lang.reflect.Type;
 import java.util.EnumSet;
 
 public class JacksonJsonpMapper extends JsonpMapperBase {
@@ -76,8 +77,8 @@ public JsonProvider jsonProvider() {
     }
 
     @Override
-    protected  <T> JsonpDeserializer<T> getDefaultDeserializer(Class<T> clazz) {
-        return new JacksonValueParser<>(clazz);
+    protected  <T> JsonpDeserializer<T> getDefaultDeserializer(Type type) {
+        return new JacksonValueParser<>(type);
     }
 
     @Override
@@ -103,11 +104,11 @@ public <T> void serialize(T value, JsonGenerator generator) {
 
     private class JacksonValueParser<T> extends JsonpDeserializerBase<T> {
 
-        private final Class<T> clazz;
+        private final Type type;
 
-        protected JacksonValueParser(Class<T> clazz) {
+        protected JacksonValueParser(Type type) {
             super(EnumSet.allOf(JsonParser.Event.class));
-            this.clazz = clazz;
+            this.type = type;
         }
 
         @Override
@@ -120,7 +121,7 @@ public T deserialize(JsonParser parser, JsonpMapper mapper, JsonParser.Event eve
             com.fasterxml.jackson.core.JsonParser jkParser = ((JacksonJsonpParser)parser).jacksonParser();
 
             try {
-                return objectMapper.readValue(jkParser, clazz);
+                return objectMapper.readValue(jkParser, objectMapper().constructType(type));
             } catch(IOException ioe) {
                 throw JacksonUtils.convertException(ioe);
             }
diff --git a/java-client/src/main/java/co/elastic/clients/json/jsonb/JsonbJsonpMapper.java b/java-client/src/main/java/co/elastic/clients/json/jsonb/JsonbJsonpMapper.java
index d5f198fdd..c936f92f4 100644
--- a/java-client/src/main/java/co/elastic/clients/json/jsonb/JsonbJsonpMapper.java
+++ b/java-client/src/main/java/co/elastic/clients/json/jsonb/JsonbJsonpMapper.java
@@ -34,6 +34,7 @@
 
 import java.io.CharArrayReader;
 import java.io.CharArrayWriter;
+import java.lang.reflect.Type;
 import java.util.EnumSet;
 
 public class JsonbJsonpMapper extends JsonpMapperBase {
@@ -60,8 +61,8 @@ public <T> JsonpMapper withAttribute(String name, T value) {
     }
 
     @Override
-    protected <T> JsonpDeserializer<T> getDefaultDeserializer(Class<T> clazz) {
-        return new Deserializer<>(clazz);
+    protected <T> JsonpDeserializer<T> getDefaultDeserializer(Type type) {
+        return new Deserializer<>(type);
     }
 
     @Override
@@ -86,11 +87,11 @@ public JsonProvider jsonProvider() {
     }
 
     private class Deserializer<T> extends JsonpDeserializerBase<T> {
-        private final Class<T> clazz;
+        private final Type type;
 
-        Deserializer(Class<T> clazz) {
+        Deserializer(Type type) {
             super(EnumSet.allOf(JsonParser.Event.class));
-            this.clazz = clazz;
+            this.type = type;
         }
 
         @Override
@@ -106,7 +107,7 @@ public T deserialize(JsonParser parser, JsonpMapper mapper, JsonParser.Event eve
             generator.close();
 
             CharArrayReader car = new CharArrayReader(caw.toCharArray());
-            return jsonb.fromJson(car, clazz);
+            return jsonb.fromJson(car, type);
         }
     }
 
diff --git a/java-client/src/main/java/co/elastic/clients/util/MissingRequiredPropertyException.java b/java-client/src/main/java/co/elastic/clients/util/MissingRequiredPropertyException.java
index 0a628c11b..e5dd0d3e3 100644
--- a/java-client/src/main/java/co/elastic/clients/util/MissingRequiredPropertyException.java
+++ b/java-client/src/main/java/co/elastic/clients/util/MissingRequiredPropertyException.java
@@ -26,8 +26,9 @@
  * available in {@link ApiTypeHelper} to disable checks. Use with caution.
  */
 public class MissingRequiredPropertyException extends RuntimeException {
-    private Class<?> clazz;
-    private String property;
+    private final Class<?> clazz;
+    private final String property;
+
     public MissingRequiredPropertyException(Object obj, String property) {
         super("Missing required property '" + obj.getClass().getSimpleName() + "." + property + "'");
         this.clazz = obj.getClass();
diff --git a/java-client/src/test/java/co/elastic/clients/elasticsearch/json/JsonpMapperTest.java b/java-client/src/test/java/co/elastic/clients/elasticsearch/json/JsonpMapperTest.java
index 02ecbf783..df2cae7fa 100644
--- a/java-client/src/test/java/co/elastic/clients/elasticsearch/json/JsonpMapperTest.java
+++ b/java-client/src/test/java/co/elastic/clients/elasticsearch/json/JsonpMapperTest.java
@@ -23,6 +23,7 @@
 import co.elastic.clients.json.jackson.JacksonJsonpMapper;
 import co.elastic.clients.json.jsonb.JsonbJsonpMapper;
 import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.PropertyNamingStrategies;
 import jakarta.json.stream.JsonGenerator;
@@ -32,8 +33,11 @@
 
 import java.io.StringReader;
 import java.io.StringWriter;
+import java.lang.reflect.Type;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 public class JsonpMapperTest extends Assertions {
 
@@ -69,6 +73,40 @@ public void testJacksonCustomMapper() {
         testDeserialize(mapper, json);
     }
 
+    @Test
+    public void testDeserializeWithType() {
+
+        String json = "{\"foo\":{\"int_value\":1,\"double_value\":1.0},\"bar\":{\"int_value\":2,\"double_value\":2.0}}";
+
+        ObjectMapper jkMapper = new ObjectMapper();
+        jkMapper.setPropertyNamingStrategy(PropertyNamingStrategies.SNAKE_CASE);
+        JacksonJsonpMapper mapper = new JacksonJsonpMapper(jkMapper);
+
+        // With type erasure, map values are raw json nodes
+        {
+            JsonParser parser = mapper.jsonProvider().createParser(new StringReader(json));
+            Map<String, SomeClass> map = new HashMap<>();
+            map = mapper.deserialize(parser, (Type) map.getClass());
+
+            Map<String, SomeClass> finalMap = map;
+            assertThrows(ClassCastException.class, () -> {
+                assertEquals(1, finalMap.get("foo").intValue);
+            });
+        }
+
+        // Use a j.l.reflect.Type to deserialize map values correctly
+        {
+            TypeReference<Map<String, SomeClass>> typeRef = new TypeReference<Map<String, SomeClass>>() {};
+
+            JsonParser parser = mapper.jsonProvider().createParser(new StringReader(json));
+            Map<String, SomeClass> map = mapper.deserialize(parser, typeRef.getType());
+
+            System.out.println(map);
+            assertEquals(1, map.get("foo").intValue);
+            assertEquals(2, map.get("bar").intValue);
+        }
+    }
+
     private void testSerialize(JsonpMapper mapper, String expected) {
 
         SomeClass something = new SomeClass();
diff --git a/java-client/src/test/java/co/elastic/clients/elasticsearch/model/ModelTestCase.java b/java-client/src/test/java/co/elastic/clients/elasticsearch/model/ModelTestCase.java
index c066c54b5..f8e10a643 100644
--- a/java-client/src/test/java/co/elastic/clients/elasticsearch/model/ModelTestCase.java
+++ b/java-client/src/test/java/co/elastic/clients/elasticsearch/model/ModelTestCase.java
@@ -32,6 +32,7 @@
 import java.io.StringReader;
 import java.io.StringWriter;
 import java.lang.reflect.Method;
+import java.lang.reflect.Type;
 import java.util.Random;
 
 /**
@@ -93,14 +94,22 @@ public static <T> String toJson(T value, JsonpMapper mapper) {
     }
 
     public static <T> T fromJson(String json, Class<T> clazz, JsonpMapper mapper) {
+        return fromJson(json, (Type)clazz, mapper);
+    }
+
+    public static <T> T fromJson(String json, Type type, JsonpMapper mapper) {
         JsonParser parser = mapper.jsonProvider().createParser(new StringReader(json));
-        return mapper.deserialize(parser, clazz);
+        return mapper.deserialize(parser, type);
     }
 
     protected <T> T fromJson(String json, Class<T> clazz) {
         return fromJson(json, clazz, mapper);
     }
 
+    protected <T> T fromJson(String json, Type type) {
+        return fromJson(json, type, mapper);
+    }
+
     @SuppressWarnings("unchecked")
     protected <T> T checkJsonRoundtrip(T value, String expectedJson) {
         assertEquals(expectedJson, toJson(value));